Objectives
Corneal confocal microscopy (
CCM
) is a noninvasive ophthalmic technique that identifies corneal nerve degeneration in a range of peripheral neuropathies and in patients with multiple sclerosis, Parkinson's disease, and amyotrophic lateral sclerosis. We sought to determine whether there is any association of corneal nerve fiber measures with cognitive function and functional independence in patients with
MCI
and dementia.
Methods
In this study, 76 nondiabetic participants with
MCI
(
n
= 30), dementia (
n
= 26), and healthy age‐matched controls (
n
= 20) underwent assessment of cognitive and physical function and
CCM
.
Results
There was a progressive reduction in corneal nerve fiber density (
CNFD
), branch density (
CNBD
), and fiber length (
CNFL
) (
P
< 0.0001) in patients with
MCI
and dementia compared to healthy controls. Adjusted for confounders, all three corneal nerve fiber measures were significantly associated with cognitive function (
P
< 0.05) and functional independence (
P
< 0.01) in
MCI
and dementia. The area under the
ROC
curve to distinguish
MCI
with
CNFD
,
CNBD
, and
CNFL
was 69.1%, 73.2%, and 73.0% and for dementia it was 84.8%, 84.2%, and 86.2%, respectively.
Interpretation
CCM
demonstrates corneal nerve fiber loss, which is associated with a decline in cognitive function and functional independence in patients with
MCI
and dementia.